tor-browser

The Tor Browser
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TaskFactory.h (2881B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      3 /* This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef mozilla_plugins_TaskFactory_h
      8 #define mozilla_plugins_TaskFactory_h
      9 
     10 #include <base/task.h>
     11 
     12 #include <utility>
     13 
     14 /*
     15 * This is based on the ScopedRunnableMethodFactory from
     16 * ipc/chromium/src/base/task.h Chromium's factories assert if tasks are created
     17 * and run on different threads, which is something we need to do in
     18 * PluginModuleParent (hang UI vs. main thread). TaskFactory just provides
     19 * cancellable tasks that don't assert this. This version also allows both
     20 * ScopedMethod and regular Tasks to be generated by the same Factory object.
     21 */
     22 
     23 namespace mozilla {
     24 namespace ipc {
     25 
     26 template <class T>
     27 class TaskFactory : public RevocableStore {
     28 private:
     29  template <class TaskType>
     30  class TaskWrapper : public TaskType {
     31   public:
     32    template <typename... Args>
     33    explicit TaskWrapper(RevocableStore* store, Args&&... args)
     34        : TaskType(std::forward<Args>(args)...), revocable_(store) {}
     35 
     36    NS_IMETHOD Run() override {
     37      if (!revocable_.revoked()) TaskType::Run();
     38      return NS_OK;
     39    }
     40 
     41   private:
     42    Revocable revocable_;
     43  };
     44 
     45 public:
     46  explicit TaskFactory(T* object) : object_(object) {}
     47 
     48  template <typename TaskParamType, typename... Args>
     49  inline already_AddRefed<TaskParamType> NewTask(Args&&... args) {
     50    typedef TaskWrapper<TaskParamType> TaskWrapper;
     51    RefPtr<TaskWrapper> task =
     52        new TaskWrapper(this, std::forward<Args>(args)...);
     53    return task.forget();
     54  }
     55 
     56  template <class Method, typename... Args>
     57  inline already_AddRefed<Runnable> NewRunnableMethod(Method method,
     58                                                      Args&&... args) {
     59    typedef decltype(base::MakeTuple(std::forward<Args>(args)...)) ArgTuple;
     60    typedef RunnableMethod<Method, ArgTuple> RunnableMethod;
     61    typedef TaskWrapper<RunnableMethod> TaskWrapper;
     62 
     63    RefPtr<TaskWrapper> task = new TaskWrapper(
     64        this, object_, method, base::MakeTuple(std::forward<Args>(args)...));
     65 
     66    return task.forget();
     67  }
     68 
     69 protected:
     70  template <class Method, class Params>
     71  class RunnableMethod : public Runnable {
     72   public:
     73    RunnableMethod(T* obj, Method meth, const Params& params)
     74        : Runnable("ipc::TaskFactory::RunnableMethod"),
     75          obj_(obj),
     76          meth_(meth),
     77          params_(params) {}
     78 
     79    NS_IMETHOD Run() override {
     80      DispatchToMethod(obj_, meth_, params_);
     81      return NS_OK;
     82    }
     83 
     84   private:
     85    T* obj_;
     86    Method meth_;
     87    Params params_;
     88  };
     89 
     90 private:
     91  T* object_;
     92 };
     93 
     94 }  // namespace ipc
     95 }  // namespace mozilla
     96 
     97 #endif  // mozilla_plugins_TaskFactory_h